Salt SSH

Execute salt commands and states over ssh without installing a salt-minion.


Getting Started

Salt SSH is very easy to use, simply set up a basic roster file of the systems to connect to and run salt-ssh commands in a similar way as standard salt commands.

  • Salt ssh is considered production ready in version 2014.7.0
  • Python is required on the remote system (unless using the -r option to send raw ssh commands)
  • On many systems, the salt-ssh executable will be in its own package, usually named salt-ssh
  • The Salt SSH system does not supersede the standard Salt communication systems, it simply offers an SSH-based alternative that does not require ZeroMQ and a remote agent. Be aware that since all communication with Salt SSH is executed via SSH it is substantially slower than standard Salt with ZeroMQ.
  • At the moment fileserver operations must be wrapped to ensure that the relevant files are delivered with the salt-ssh commands. The state module is an exception, which compiles the state run on the master, and in the process finds all the references to salt:// paths and copies those files down in the same tarball as the state run. However, needed fileserver wrappers are still under development.

Salt SSH Roster

The roster system in Salt allows for remote minions to be easily defined.

Note

See the SSH roster docs for more details.

Simply create the roster file, the default location is /etc/salt/roster:

web1: 192.168.42.1

This is a very basic roster file where a Salt ID is being assigned to an IP address. A more elaborate roster can be created:

web1:
  host: 192.168.42.1 # The IP addr or DNS hostname
  user: fred         # Remote executions will be executed as user fred
  passwd: foobarbaz  # The password to use for login, if omitted, keys are used
  sudo: True         # Whether to sudo to root, not enabled by default
web2:
  host: 192.168.42.2

Note

sudo works only if NOPASSWD is set for user in /etc/sudoers: fred ALL=(ALL) NOPASSWD: ALL

Deploy ssh key for salt-ssh

By default, salt-ssh will generate key pairs for ssh, the default path will be /etc/salt/pki/master/ssh/salt-ssh.rsa

You can use ssh-copy-id, (the OpenSSH key deployment tool) to deploy keys to your servers.

ssh-copy-id -i /etc/salt/pki/master/ssh/salt-ssh.rsa.pub user@server.demo.com

One could also create a simple shell script, named salt-ssh-copy-id.sh as follows:

#!/bin/bash
if [ -z $1 ]; then
   echo $0 user@host.com
   exit 0
fi
ssh-copy-id -i /etc/salt/pki/master/ssh/salt-ssh.rsa.pub $1

Note

Be certain to chmod +x salt-ssh-copy-id.sh.

./salt-ssh-copy-id.sh user@server1.host.com
./salt-ssh-copy-id.sh user@server2.host.com

Once keys are successfully deployed, salt-ssh can be used to control them.

Alternatively ssh agent forwarding can be used by setting the priv to agent-forwarding.

Calling Salt SSH

Note

salt-ssh on RHEL/CentOS 5

The salt-ssh command requires at least python 2.6, which is not installed by default on RHEL/CentOS 5. An easy workaround in this situation is to use the -r option to run a raw shell command that installs python26:

salt-ssh centos-5-minion -r 'yum -y install epel-release ; yum -y install python26'

The salt-ssh command can be easily executed in the same way as a salt command:

salt-ssh '*' test.ping

Commands with salt-ssh follow the same syntax as the salt command.

The standard salt functions are available! The output is the same as salt and many of the same flags are available. Please see http://docs.saltstack.com/ref/cli/salt-ssh.html for all of the available options.

Raw Shell Calls

By default salt-ssh runs Salt execution modules on the remote system, but salt-ssh can also execute raw shell commands:

salt-ssh '*' -r 'ifconfig'

States Via Salt SSH

The Salt State system can also be used with salt-ssh. The state system abstracts the same interface to the user in salt-ssh as it does when using standard salt. The intent is that Salt Formulas defined for standard salt will work seamlessly with salt-ssh and vice-versa.

The standard Salt States walkthroughs function by simply replacing salt commands with salt-ssh.

Targeting with Salt SSH

Due to the fact that the targeting approach differs in salt-ssh, only glob and regex targets are supported as of this writing, the remaining target systems still need to be implemented.

Note

By default, Grains are settable through salt-ssh. By default, these grains will not be persisted across reboots.

See the "thin_dir" setting in Roster documentation for more details.

Configuring Salt SSH

Salt SSH takes its configuration from a master configuration file. Normally, this file is in /etc/salt/master. If one wishes to use a customized configuration file, the -c option to Salt SSH facilitates passing in a directory to look inside for a configuration file named master.

Minion Config

New in version 2015.5.1.

Minion config options can be defined globally using the master configuration option ssh_minion_opts. It can also be defined on a per-minion basis with the minion_opts entry in the roster.

Running Salt SSH as non-root user

By default, Salt read all the configuration from /etc/salt/. If you are running Salt SSH with a regular user you have to modify some paths or you will get "Permission denied" messages. You have to modify two parameters: pki_dir and cachedir. Those should point to a full path writable for the user.

It's recommended not to modify /etc/salt for this purpose. Create a private copy of /etc/salt for the user and run the command with -c /new/config/path.

Define CLI Options with Saltfile

If you are commonly passing in CLI options to salt-ssh, you can create a Saltfile to automatically use these options. This is common if you're managing several different salt projects on the same server.

So you can cd into a directory that has a Saltfile with the following YAML contents:

salt-ssh:
  config_dir: path/to/config/dir
  ssh_max_procs: 30
  ssh_wipe: True

Instead of having to call salt-ssh --config-dir=path/to/config/dir --max-procs=30 --wipe \* test.ping you can call salt-ssh \* test.ping.

Boolean-style options should be specified in their YAML representation.

Note

The option keys specified must match the destination attributes for the options specified in the parser salt.utils.parsers.SaltSSHOptionParser. For example, in the case of the --wipe command line option, its dest is configured to be ssh_wipe and thus this is what should be configured in the Saltfile. Using the names of flags for this option, being wipe: True or w: True, will not work.

Note

For the Saltfile to be automatically detected it needs to be named Saltfile with a capital S and be readable by the user running salt-ssh.

Debugging salt-ssh

One common approach for debugging salt-ssh is to simply use the tarball that salt ships to the remote machine and call salt-call directly.

To determine the location of salt-call, simply run salt-ssh with the -ltrace flag and look for a line containing the string, SALT_ARGV. This contains the salt-call command that salt-ssh attempted to execute.

It is recommended that one modify this command a bit by removing the -l quiet, --metadata and --output json to get a better idea of what's going on on the target system.